#Normal Mode
def cal(ax,ay,bx,by):
    p = 0.5
    ansx = ax * (1 - p) + bx * p
    ansy = ay * (1 - p) + by * p
    return (ansx,ansy)
print(cal(2,1,6,5))
#pyg zero
def cal(ax,ay,bx,by):
    p = 0.5
    ansx = ax * (1 - p) + bx * p
    ansy = ay * (1 - p) + by * p
    return ansx,ansy
x,y = cal(200,100,600,500)
#I'm afraid if the data is too small for the position x and y,so I change it into 200 100 600 500
def update():
    global x,y
    screen.draw.line((200,100),(600,500),(200,0,0))
    screen.draw.filled_circle((x,y),4,(0,200,0))